H Q2-) The waste flow 18000 m'/day is treated by activated sludge process to reduce 97.5% of influent BOD, concentration of 250 mg/L. The ratio of formed cell mass and substrate utilized mass are 0.4 and 0.8, respectively, MLVSS = 3500 mg/L, return sludge (Xr) = 8000 mg/L, decay growth rate= 0.05, and 0, 10 days. Find the following: 1. Reactor volume and hydraulic retention time. 3. The daily amount of wasted sludge. 5. Food to microorganisms' ratio. 2. The volumetric organic loading 4. The recycle ratio, and treatment efficiency.

H Q2-) The waste flow 18000 m'/day is treated by activated sludge process to reduce 97.5% of influent BOD, concentration of 250 mg/L. The ratio of formed cell mass and substrate utilized mass are 0.4 and 0.8, respectively, MLVSS = 3500 mg/L, return sludge (Xr) = 8000 mg/L, decay growth rate= 0.05, and 0, 10 days. Find the following: 1. Reactor volume and hydraulic retention time. 3. The daily amount of wasted sludge. 5. Food to microorganisms' ratio. 2. The volumetric organic loading 4. The recycle ratio, and treatment efficiency.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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An activated sludge plant with recycle is evaluating its secondary clarification system. Settling column tests are conducted and analyzed for settling velocities at different initial solids concentrations. The data are provided below. The plant flow rate is 10,000 m3/d, with a recirculation ratio of 0.5. The MLSS in the reactor is 4000 mg/L. The desired underflow concentration is 17,000 mg/L. Solids concentration mg/L Settling velocity m/h 1500 6.5 3000 5.1 4500 4 6000 2.95 7500 2 9000 1.4 12,000 0.5 15,000 0.27 17,000 0.2 a. Calculate the required surface area if one clarifier is used. b. Calculate underflow rate, underflow velocity, and overflow rate for single clarifier design. Clearly state your assumptions. c. Calculate the required surface area if two clarifiers are used
A wastewater treatment plant uses an activated sludge process to treat 0.2 m3/s of primary effluent. The concentration of the mixed liquor is 2,000 mg/L MLVSS (Mixed liquor volatile suspended solids), while the RAS (recycled activated sludge) concentration is 10,000 mg/L MLVSS. The substrate concentration in the primary effluent is 210 mg/L BOD5. The F/M ratio is 0.5 mg BOD5/(mg MLVSS-d) and the solids retention time is 8.5 d. What is the volume of the activated sludge tank? 2.What is the WAS (waste activated sludge) flowrate? 3.What is the flowrate of the secondary treated effluent? 4.What is the RAS (recycled activated sludge) flowrate? 5.What is the hydraulic residence time for the activated sludge tank?
A wastewater treatment uses an activated sludge process for secondary treatment of 0.3 m^3/s of primary effluent. The activated sludge has a biomass concentration of 2,100 mg VSS/L, and the return activated sludge line (also known as RAS) concentration is 10,000 mg VSS/L. The substrate concentration in the primary effluent is 220 mg BOD5/L. The F/M ratio for the activated sludge tank is 0.52 mg BOD5 × mg VSS^-1 × d^-1 , and the cell residence time is 9.0 d. (a) What is the volume of the activated sludge tank?(b) What is the waste line (also known as WAS) flow rate?(c) What is the flow rate of the effluent from the entire system?(d) What is the hydraulic residence time for the activated sludge tank? Hint: You will need to also write a mass balance for biomass X around the secondary clarifier, and a flow balance around the secondary clarifier, as part of the solution.
a) An activated sludge plant with recycle is evaluating its secondary clarification system. Settling column tests are conducted and analyzed for settling velocities at different initial solids concentrations. The data are provided below. The plant flow rate is 10,000 m3/d, with a recirculation ratio of 0.5. The MLSS in the reactor is 4000 mg/L. The desired underflow concentration is 17,000 mg/L. Solids concentration mg/L Settling velocity m/h 1500 6.5 3000 5.1 4500 4 6000 2.95 7500 2 9000 1.4 12,000 0.5 15,000 0.27 17,000 0.2 b) Design secondary clarifiers for the activated sludge plant of problem a), with a recycle ratio of 0.6. Calculate the required surface area if two clarifiers are used. Also calculate underflow rate, underflow velocity, and overflow rates. Clearly state your assumptions.
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Consider a well-mixed aeration lagoon to remove BOD from a waste stream flowing at 5MGD. The lagoon is 100-m long, 30-m wide and 3-m deep. Given the default microbial kineticparameters (Ks = 60 mg BOD5/L, μm = 3 day-1, kd = 0.06 day-1) calculate the concentration ofBOD5 in the waste stream leaving the lagoon.
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